Method of making chamber with tensile member

ABSTRACT

A fluid-filled may include including an outer barrier, a tensile member, and a fluid. The tensile member may be located within barrier and formed from a textile element that includes a pair of spaced layers joined by a plurality of connecting members. A method of manufacturing the chamber may include locating a textile tensile member between two polymer elements. Pressure and heat are applied to the tensile member and the polymer elements in a first area and in a second area. The pressure is greater in the first area than in the second area. In addition, the polymer elements are bonded together around a periphery of the tensile member.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of prior pending nonprovisionalapplication Ser. No. 12/123,646, filed 20 May 2008, the entiredisclosure of which is incorporated herein by reference.

BACKGROUND

Articles of footwear generally include two primary elements, an upperand a sole structure. The upper is formed from a variety of materialelements (e.g., textiles, foam, leather, and synthetic leather) that arestitched or adhesively bonded together to form a void on the interior ofthe footwear for comfortably and securely receiving a foot. An ankleopening through the material elements provides access to the void,thereby facilitating entry and removal of the foot from the void. Inaddition, a lace is utilized to modify the dimensions of the void andsecure the foot within the void.

The sole structure is located adjacent to a lower portion of the upperand is generally positioned between the foot and the ground. In manyarticles of footwear, including athletic footwear, the sole structureconventionally incorporates an insole, a midsole, and an outsole. Theinsole is a thin compressible member located within the void andadjacent to a lower surface of the void to enhance footwear comfort. Themidsole, which may be secured to a lower surface of the upper andextends downward from the upper, forms a middle layer of the solestructure. In addition to attenuating ground reaction forces (i.e.,providing cushioning for the foot), the midsole may limit foot motionsor impart stability, for example. The outsole, which may be secured to alower surface of the midsole, forms the ground-contacting portion of thefootwear and is usually fashioned from a durable and wear-resistantmaterial that includes texturing to improve traction.

The conventional midsole is primarily formed from a foamed polymermaterial, such as polyurethane or ethylvinylacetate, that extendsthroughout a length and width of the footwear. In some articles offootwear, the midsole may include a variety of additional footwearelements that enhance the comfort or performance of the footwear,including plates, moderators, fluid-filled chambers, lasting elements,or motion control members. In some configurations, any of theseadditional footwear elements may be located between the midsole andeither of the upper and outsole, embedded within the midsole, orencapsulated by the foamed polymer material of the midsole, for example.Although many conventional midsoles are primarily formed from a foamedpolymer material, fluid-filled chambers or other non-foam structures mayform a majority of some midsole configurations.

SUMMARY

A method of manufacturing a fluid-filled chamber is disclosed. Themethod includes locating a textile tensile member between two polymerelements. Pressure is applied to the tensile member and the polymerelements in a first area and in a second area. The pressure may begreater in the first area than in the second area. In addition, thepolymer elements are bonded together around a periphery of the tensilemember.

The advantages and features of novelty characterizing aspects of theinvention are pointed out with particularity in the appended claims. Togain an improved understanding of the advantages and features ofnovelty, however, reference may be made to the following descriptivematter and accompanying figures that describe and illustrate variousconfigurations and concepts related to the invention.

FIGURE DESCRIPTIONS

The foregoing Summary and the following Detailed Description will bebetter understood when read in conjunction with the accompanyingfigures.

FIG. 1 is a lateral side elevational view of an article of footwearincorporating a fluid-filled chamber.

FIG. 2 is a medial side elevational view of the article of footwear.

FIG. 3 is a perspective view of the chamber.

FIG. 4 is an exploded perspective view of the chamber.

FIG. 5 is a top plan view of the chamber.

FIG. 6A-6D are cross-sectional views of the chamber, as defined bysection lines 6A-6D in FIG. 5.

FIG. 7 is a lateral side elevational view of the chamber.

FIG. 8 is a medial side elevational view of the chamber.

FIG. 9 is a bottom plan view of the chamber.

FIG. 10 is a perspective view of a tensile member of the chamber.

FIG. 11 is a top plan view of the tensile member.

FIG. 12 is a lateral side elevational view of the tensile member.

FIG. 13 is a medial side elevational view of the tensile member.

FIG. 14 is a bottom plan view of the tensile member.

FIG. 15 is a perspective view of a laminating apparatus.

FIGS. 16A-16C are schematic side elevational views of the laminatingapparatus depicting steps in a laminating process for the chamber.

FIG. 17 is a perspective view of elements of the chamber following thelaminating process.

FIG. 18 is a perspective view of a bonding apparatus.

FIGS. 19A-19C are schematic side elevational views of the bondingapparatus depicting steps in a bonding process for the chamber.

FIG. 20 is a perspective view of the chamber and residual portions ofpolymer sheets forming the chamber following the bonding process.

FIG. 21 is a perspective view of a thermoforming apparatus for formingthe chamber.

FIGS. 22A-22C are schematic cross-sectional views of the thermoformingapparatus, as defined by section line 22 in FIG. 21, depicting steps ina thermoforming process for the chamber.

FIG. 23 is a perspective view of the chamber and residual portions ofpolymer sheets forming the chamber following the thermoforming process.

FIGS. 24A-24C are top plan views of additional configurations of thechamber.

FIGS. 25A-25C are lateral side elevational views corresponding with FIG.8 and depicting additional configurations of the chamber.

FIGS. 26A-26D are cross-sectional views corresponding with FIG. 6A anddepicting additional configurations of the chamber.

FIG. 27 is an elevational view of a ball incorporating a pluralitypanels with the configurations of fluid-filled chambers.

FIG. 28 is a top plan view of one of the panels.

FIG. 29 is a cross-sectional view of the panel, as defined by sectionline 29-29 in FIG. 28.

FIGS. 30A and 30B are cross-sectional views corresponding with FIG. 22Aand depicting further manufacturing configurations of the thermoformingapparatus and further manufacturing processes.

DETAILED DESCRIPTION

The following discussion and accompanying figures disclose variousconfigurations of fluid-filled chambers and methods for manufacturingthe chambers. Although the chambers are disclosed with reference tofootwear having a configuration that is suitable for running, conceptsassociated with the chambers may be applied to a wide range of athleticfootwear styles, including basketball shoes, cross-training shoes,football shoes, golf shoes, hiking shoes and boots, ski and snowboardingboots, soccer shoes, tennis shoes, and walking shoes, for example.Concepts associated with the chambers may also be utilized with footwearstyles that are generally considered to be non-athletic, including dressshoes, loafers, and sandals. In addition to footwear, the chambers maybe incorporated into other types of apparel and athletic equipment,including helmets, gloves, and protective padding for sports such asfootball and hockey. Similar chambers may also be incorporated intocushions and other compressible structures utilized in household goodsand industrial products. Accordingly, chambers incorporating theconcepts disclosed herein may be utilized with a variety of products.

General Footwear Structure

An article of footwear 10 is depicted in FIGS. 1 and 2 as including anupper 20 and a sole structure 30. For reference purposes, footwear 10may be divided into three general regions: a forefoot region 11, amidfoot region 12, and a heel region 13, as shown in FIGS. 1 and 2.Footwear 10 also includes a lateral side 14 and a medial side 15.Forefoot region 11 generally includes portions of footwear 10corresponding with the toes and the joints connecting the metatarsalswith the phalanges. Midfoot region 12 generally includes portions offootwear 10 corresponding with the arch area of the foot, and heelregion 13 corresponds with rear portions of the foot, including thecalcaneus bone. Lateral side 14 and medial side 15 extend through eachof regions 11-13 and correspond with opposite sides of footwear 10.Regions 11-13 and sides 14-15 are not intended to demarcate preciseareas of footwear 10. Rather, regions 11-13 and sides 14-15 are intendedto represent general areas of footwear 10 to aid in the followingdiscussion. In addition to footwear 10, regions 11-13 and sides 14-15may also be applied to upper 20, sole structure 30, and individualelements thereof.

Upper 20 is depicted as having a substantially conventionalconfiguration incorporating a plurality material elements (e.g.,textile, foam, leather, and synthetic leather) that are stitched oradhesively bonded together to form an interior void for securely andcomfortably receiving a foot. The material elements may be selected andlocated with respect to upper 20 in order to selectively impartproperties of durability, air-permeability, wear-resistance,flexibility, and comfort, for example. An ankle opening 21 in heelregion 13 provides access to the interior void. In addition, upper 20may include a lace 22 that is utilized in a conventional manner tomodify the dimensions of the interior void, thereby securing the footwithin the interior void and facilitating entry and removal of the footfrom the interior void. Lace 22 may extend through apertures in upper20, and a tongue portion of upper 20 may extend between the interiorvoid and lace 22. Given that various aspects of the present applicationprimarily relate to sole structure 30, upper 20 may exhibit the generalconfiguration discussed above or the general configuration ofpractically any other conventional or non-conventional upper.Accordingly, the overall structure of upper 20 may vary significantly.

Sole structure 30 is secured to upper 20 and has a configuration thatextends between upper 20 and the ground. In effect, therefore, solestructure 30 is located to extend between the foot and the ground. Inaddition to attenuating ground reaction forces (i.e., providingcushioning for the foot), sole structure 30 may provide traction, impartstability, and limit various foot motions, such as pronation. Theprimary elements of sole structure 30 are a midsole 31 and an outsole32. Midsole 31 may be formed from a polymer foam material, such aspolyurethane or ethylvinylacetate, that encapsulates a fluid-filledchamber 33. In addition to the polymer foam material and chamber 33,midsole 31 may incorporate one or more additional footwear elements thatenhance the comfort, performance, or ground reaction force attenuationproperties of footwear 10, including plates, moderators, lastingelements, or motion control members. Outsole 32, which may be absent insome configurations of footwear 10, is secured to a lower surface ofmidsole 31 and may be formed from a rubber material that provides adurable and wear-resistant surface for engaging the ground. In addition,outsole 32 may also be textured to enhance the traction (i.e., friction)properties between footwear 10 and the ground. Sole structure 30 mayalso incorporate an insole or sockliner that is located with in the voidin upper 20 and adjacent a plantar (i.e., lower) surface of the foot toenhance the comfort of footwear 10.

Chamber Configuration

Chamber 33 is depicted individually in FIGS. 3-9 as having aconfiguration that is suitable for footwear applications. Whenincorporated into footwear 10, chamber 33 has a shape that fits within aperimeter of midsole 31 and substantially extends from forefoot region11 to heel region 13 and also from lateral side 14 to medial side 15,thereby corresponding with a general outline of the foot. Although thepolymer foam material of midsole 31 is depicted as forming a sidewall ofmidsole 31, chamber 33 may form a portion of the sidewall in someconfigurations of footwear 10. When the foot is located within upper 20,chamber 33 extends under substantially all of the foot in order toattenuate ground reaction forces that are generated when sole structure30 is compressed between the foot and the ground during variousambulatory activities, such as running and walking. In otherconfigurations, chamber 33 may extend under only a portion of the foot.

The primary elements of chamber 33 are a barrier 40 and a tensile member50. Barrier 40 forms an exterior of chamber 33 and (a) defines aninterior void that receives both a pressurized fluid and tensile member50 and (b) provides a durable sealed barrier for retaining thepressurized fluid within chamber 33. The polymer material of barrier 40includes an upper barrier portion 41, an opposite lower barrier portion42, and a sidewall barrier portion 43 that extends around a periphery ofchamber 33 and between barrier portions 41 and 42. Tensile member 50 islocated within the interior void and has a configuration of aspacer-knit textile that includes an upper tensile layer 51, an oppositelower tensile layer 52, and a plurality of connecting members 53 thatextend between tensile layers 51 and 52. Whereas upper tensile layer 51is secured to an inner surface of upper barrier portion 41, lowertensile layer 52 is secured to an inner surface of lower barrier portion42. Although discussed in greater detail below, either adhesive bondingor thermobonding may be utilized to secure tensile member 50 to barrier40.

A variety of processes, two of which are discussed in greater detailbelow, may be utilized to manufacture chamber 33. In general, themanufacturing processes involve (a) securing a pair of polymer sheets,which form barrier portions 41-43, to opposite sides of tensile member50 (i.e., to tensile layers 51 and 52) and (b) forming a peripheral bond44 that joins a periphery of the polymer sheets and extends aroundsidewall barrier portion 43. A fluid may then be injected into theinterior void and pressurized. The pressurized fluid exerts an outwardforce upon barrier 40, which tends to separate barrier portions 41 and42. Tensile member 50, however, is secured to each of barrier portions41 and 42 in order to retain the intended shape of chamber 33 whenpressurized. More particularly, connecting members 53 extend across theinterior void and are placed in tension by the outward force of thepressurized fluid upon barrier 40, thereby preventing barrier 40 fromexpanding outward and retaining the intended shape of chamber 33.Whereas peripheral bond 44 joins the polymer sheets to form a seal thatprevents the fluid from escaping, tensile member 50 prevents barrier 40from expanding outward or otherwise distending due to the pressure ofthe fluid. That is, tensile member 50 effectively limits the expansionof chamber 33 to retain an intended shape of barrier portions 41 and 42.

Chamber 33 is shaped and contoured to provide a structure that issuitable for footwear applications. As noted above, chamber 33 has ashape that fits within a perimeter of midsole 31 and extends undersubstantially all of the foot, thereby corresponding with a generaloutline of the foot. In addition, surfaces corresponding with barrierportions 41 and 42 are contoured in a manner that is suitable forfootwear applications. With reference to FIGS. 7 and 8, for example,chamber 33 exhibits a tapered configuration between heel region 13 andforefoot region 11. That is, the portion of chamber 33 in heel region 13exhibits a greater overall thickness than the portion of chamber 33 inforefoot region 11. When incorporated into footwear 10, the tapering ofchamber 33 ensures that the heel of the foot is slightly raised inrelation to the forefoot. In addition to tapering, chamber 33 may alsodefine depressions and protrusions that complement the generalanatomical structure of the foot.

The fluid within chamber 33 may be pressurized between zero andthree-hundred-fifty kilopascals (i.e., approximately fifty-one poundsper square inch) or more. In addition to air and nitrogen, the fluid mayinclude octafluorapropane or be any of the gasses disclosed in U.S. Pat.No. 4,340,626 to Rudy, such as hexafluoroethane and sulfur hexafluoride.In some configurations, chamber 33 may incorporate a valve or otherstructure that permits the individual to adjust the pressure of thefluid.

A wide range of polymer materials may be utilized for barrier 40. Inselecting materials for barrier 40, engineering properties of thematerial (e.g., tensile strength, stretch properties, fatiguecharacteristics, dynamic modulus, and loss tangent) as well as theability of the material to prevent the diffusion of the fluid containedby barrier 40 may be considered. When formed of thermoplastic urethane,for example, barrier 40 may have a thickness of approximately 1.0millimeter, but the thickness may range from 0.25 to 2.0 millimeters ormore, for example. In addition to thermoplastic urethane, examples ofpolymer materials that may be suitable for barrier 40 includepolyurethane, polyester, polyester polyurethane, and polyetherpolyurethane. Barrier 40 may also be formed from a material thatincludes alternating layers of thermoplastic polyurethane andethylene-vinyl alcohol copolymer, as disclosed in U.S. Pat. Nos.5,713,141 and 5,952,065 to Mitchell, et al. A variation upon thismaterial may also be utilized, wherein a center layer is formed ofethylene-vinyl alcohol copolymer, layers adjacent to the center layerare formed of thermoplastic polyurethane, and outer layers are formed ofa regrind material of thermoplastic polyurethane and ethylene-vinylalcohol copolymer. Another suitable material for barrier 40 is aflexible microlayer membrane that includes alternating layers of a gasbarrier material and an elastomeric material, as disclosed in U.S. Pat.Nos. 6,082,025 and 6,127,026 to Bonk, et al. Additional suitablematerials are disclosed in U.S. Pat. Nos. 4,183,156 and 4,219,945 toRudy. Further suitable materials include thermoplastic films containinga crystalline material, as disclosed in U.S. Pat. Nos. 4,936,029 and5,042,176 to Rudy, and polyurethane including a polyester polyol, asdisclosed in U.S. Pat. Nos. 6,013,340; 6,203,868; and 6,321,465 to Bonk,et al.

In order to facilitate bonding between tensile member 50 and barrier 40,polymer supplemental layers may be applied to each of tensile layers 51and 52. When heated, the supplemental layers soften, melt, or otherwisebegin to change state so that contact with barrier portions 41 and 42induces material from each of barrier 40 and the supplemental layers tointermingle or otherwise join with each other. Upon cooling, therefore,the supplemental layer is permanently joined with barrier 40, therebyjoining tensile member 50 with barrier 40. In some configurations,thermoplastic threads or strips may be present within tensile layers 51and 52 to facilitate bonding with barrier 40, as disclosed in U.S. Pat.No. 7,070,845 to Thomas, et al., or an adhesive may be utilized tosecure barrier 40 and tensile member 50.

Tensile Member Configuration

Tensile member 50, which is depicted individually in FIGS. 10-14,includes upper tensile layer 51, the opposite lower tensile layer 52,and the plurality of connecting members 53 that extend between tensilelayers 51 and 52. Each of tensile layers 51 and 52 have a generallycontinuous and planar configuration, although tensile layers 51 and 52angle toward each other to impart the tapered configuration between heelregion 13 and forefoot region 11. Connecting members 53 are secured toeach of tensile layers 51 and 52 and space tensile layers 51 and 52apart from each other. More particularly, the outward force of thepressurized fluid places connecting members 53 in tension and restrainsfurther outward movement of tensile layers 51 and 52 and barrierportions 41 and 42. Connecting members 53 are arranged in rows that areseparated by gaps. The use of gaps provides tensile member 50 withincreased compressibility in comparison to tensile members formed ofdouble-walled fabrics that utilize continuous connecting members,although continuous connecting members 53 may be utilized in someconfigurations of chamber 33. In comparing the lengths of connectingmembers 53, the connecting members 53 located in heel region 13 may belonger than the connecting members 53 in forefoot region 11 to impartthe tapered configuration to tensile member 50.

In each of the manufacturing processes, tensile member 50 initiallyexhibits a non-contoured configuration. More particularly, tensilelayers 51 and 52 are initially planar and parallel to each other. Duringthe manufacturing processes, however, energy (e.g., in the form of radiofrequency energy or heat) and pressure may alter the structure oftensile member 50 to impart contouring. That is, the energy and pressuremay alter the lengths of connecting members 53 between heel region 13and forefoot region 11 in order to impart the tapered configuration.More particularly, the energy and pressure may (a) deform a portion ofconnecting members 53 or (b) induce polymer material from barrier 40 orthe supplemental layers to infiltrate tensile member 50, therebyeffectively shortening the length of connecting members 53. Dependingupon the degree of energy and pressure applied, connecting members 53may be effectively shortened through both deformation and infiltrationof the polymer material.

Tensile member 50 is formed as a unitary (i.e., one-piece) textileelement having the configuration of a spacer-knit textile. A variety ofknitting techniques may be utilized to form tensile member 50 and imparta specific configuration (e.g., taper, contour, length, width,thickness) to tensile member 50. In general, knitting involves formingcourses and wales of intermeshed loops of a yarn or multiple yarns. Inproduction, knitting machines may be programmed tomechanically-manipulate yarns into the configuration of tensile member50. That is, tensile member 50 may be formed bymechanically-manipulating yarns to form a one-piece textile element thathas a particular configuration. The two major categories of knittingtechniques are weft-knitting and warp-knitting. Whereas a weft-knitfabric utilizes a single yarn within each course, a warp-knit fabricutilizes a different yarn for every stitch in a course. Various types ofweft-knitting and warp-knitting may be utilized, including wide tubecircular knitting, narrow tube circular knit jacquard, single knitcircular knit jacquard, double knit circular knit jacquard, warp knitjacquard, flat knitting, and double needle bar raschel knitting, forexample. Accordingly, a variety of knitting techniques may be utilizedin manufacturing tensile member 50.

For purposes of the present discussion, the term “yarn” or variantsthereof is intended to encompass a variety of generally one-dimensionalmaterials (e.g., filaments, fibers, threads, strings, strands, andcombinations thereof) that may be utilized to form a textile. Theproperties of tensile member 50 may relate to the specific materialsthat are utilized in the yarns. Examples of properties that may berelevant in selecting specific yarns for tensile member 50 includetensile strength, tensile modulus, density, flexibility, tenacity,resistance to abrasion, and resistance to degradation (e.g., from water,light, and chemicals). Examples of suitable materials for the yarnsinclude rayon, nylon, polyester, polyacrylic, silk, cotton, carbon,glass, aramids (e.g., para-aramid fibers and meta-aramid fibers), ultrahigh molecular weight polyethylene, and liquid crystal polymer. Althougheach of these materials exhibit properties that are suitable for tensilemember 50, each of these materials exhibit different combinations ofmaterial properties. Accordingly, the properties of yarns formed fromeach of these materials may be compared in selecting materials for theyarns within tensile member 50. Moreover, factors relating to thecombination of yarns and the type of knit or type of textile may beconsidered in selecting a specific configuration for tensile member 50.

First Manufacturing Process

Although a variety of manufacturing processes may be utilized to formchamber 33, an example of a suitable process will now be discussed. Ingeneral, the process involves (a) utilizing a laminating apparatus tosecure a pair of polymer sheets 41′ and 42′ to opposite sides of tensilemember 50 (i.e., to tensile layers 51 and 52) and then (b) utilizing abonding apparatus to form peripheral bond 44 between polymer sheets 41′and 42′. Although the laminating apparatus and the separate bondingapparatus are utilized, a single apparatus that both laminates and bondsmay also be utilized to substantially manufacture chamber 33 in a singlestep.

With reference to FIG. 15, a laminating apparatus 60 is depicted asincluding an upper portion 61 and an opposite lower portion 62. Inaddition, a spacer 63 is secured to lower portion 62 and forms anon-parallel surface with upper portion 61. Whereas opposing surfaces ofportions 61 and 62 are substantially parallel, spacer 63 has a taperedconfiguration, thereby forming a surface that is non-parallel with upperportion 61. Although the taper in spacer 63 may vary significantly, asuitable taper is 0.50 millimeters (i.e., approximately 0.020 inches)for each 30 centimeters (i.e., approximately 12 inches) across spacer63, but may range from 0.05 millimeters to 13 millimeters. That is, thethickness of spacer 63 in one area may be at least 0.50 millimetersgreater than the thickness in an area that is 30 centimeters away, orthe difference may be greater or less.

In utilizing laminating apparatus 60, tensile member 50 is locatedbetween polymer sheets 41′ and 42′, and these components of chamber 33are placed within laminating apparatus 60, as depicted in FIG. 16A. Moreparticularly, polymer sheet 41′ is located adjacent to upper portion 61,and polymer sheet 42′ is located adjacent to lower portion 62 and spacer63, with tensile member 50 being located therebetween. Once positioned,laminating apparatus 60 closes such that the components of chamber 33are compressed between upper portion 61 and spacer 63, as depicted inFIG. 16B. As discussed above, spacer 63 has a tapered configuration andforms a surface that is non-parallel with upper portion 61. The taperedconfiguration of spacer 63 provides different degrees of compression indifferent areas of polymer sheet 41′, polymer sheet 42′, and tensilemember 50. That is, the components of chamber 33 will be compressed lesswhere spacer 63 has lesser thickness, and the elements will becompressed more where spacer 63 has greater thickness. Accordingly, thenon-parallel surfaces within laminating apparatus 60 impart differentdegrees of pressure to different areas of the components of chamber 33.Furthermore, the taper in spacer 63 ensures a continuously-varyingdegree of pressure is applied to the components of chamber 33.

Although polymer sheet 41′, polymer sheet 42′, and tensile member 50 maybe oriented in different ways within laminating apparatus 60, thetapered configuration of chamber 33 may arise when portions of thecomponents of chamber 33 located in forefoot region 11 are compressedmore than portions of the components located within heel region 13. Thatis, the taper in spacer 63 may be utilized to apply greater pressure tothe portions of the components of chamber 33 located in forefoot region11 than the portions of the components located within heel region 13.

While being compressed, radio frequency energy (RF energy) may beemitted by laminating apparatus 60 in order to heat polymer sheet 41′,polymer sheet 42′, and tensile member 50. More particularly, the radiofrequency energy may pass from upper portion 61 to lower portion 62 andspacer 63. The amount of radio frequency energy passing between upperportion 61 and spacer 63 at least partially depends upon the spacingbetween upper portion 61 and spacer 63. Given the tapered configurationof spacer 63, areas of spacer 63 with greater thickness are closer toupper portion 61 than areas of spacer 63 with lesser thickness. Thecomponents of chamber 33, therefore, will be exposed to more radiofrequency energy in areas where spacer 63 has greater thickness, and thecomponents of chamber 33 will be exposed to less radio frequency energyin areas where spacer 63 has lesser thickness. Accordingly, thenon-parallel surfaces within laminating apparatus 60 impart differentdegrees of radio frequency energy to different areas of polymer sheet41′, polymer sheet 42′, and tensile member 50.

Following compression and irradiation with radio frequency energy (i.e.,heating), laminating apparatus 60 opens such that polymer sheet 41′,polymer sheet 42′, and tensile member 50 may be removed, as depicted inFIGS. 16C and 17. The compression and heating of polymer sheets 41′ and42′ caused bonding between the elements. More particularly, thecompression and heating induced polymer sheet 41′ to bond with uppertensile layer 51 and also induced polymer sheet 42′ to bond with lowertensile layer 52. In addition, the differences in compression and radiofrequency energy due to the tapering of spacer 63 effectively shortenedthe lengths of some of connecting member 53. More particularly, thecompression and heating (a) deformed a portion of connecting members 53or (b) induced polymer material from polymer sheet 41′, polymer sheet42′, or the supplemental layers to infiltrate tensile member 50, therebyeffectively shortening the lengths of connecting members 53 in the areaswhere compression and heating were greatest. Depending upon the degreeof compression and irradiation, both deformation and infiltration ofpolymer material may cause the shortening of connecting members 53.Accordingly, differences in compression and irradiation effectivelyimparted a tapered configuration to tensile member 50. That is, thegreater pressure and heat in the portions of the components of chamber33 located in forefoot region 11, as compared to the portions of thecomponents located within heel region 13, impart the taperedconfiguration to tensile member 50 and chamber 33.

Depending upon the specific materials utilized for tensile member 50 andpolymer layers 41′ and 42′, the temperature range that facilitatesbonding may extend from 120 to 200 degrees Celsius (248 to 392 degreesFahrenheit) or more. As an example, a material having alternating layersof thermoplastic polyurethane and ethylene-vinyl alcohol copolymer maybe heated to a temperature in a range of 149 to 188 degrees Celsius (300and 370 degrees Fahrenheit) to facilitate bonding. Although radiofrequency energy may be utilized, as discussed above, various radiantheaters or other devices may be utilized to heat the components ofchamber 33, or laminating apparatus 60 may be heated such that contactbetween laminating apparatus 60 and the components of chamber 33 raisesthe temperature to a level that facilitates bonding.

Based upon the above discussion, one or both of pressure and heat may beutilized to impart contouring to chamber 33. Although the pressure andheat are applied by laminating apparatus 60, the shape of tensile member50 may also be modified prior to the use of laminating apparatus 60.That is, a separate apparatus may be utilized to compress or heattensile member 50 in order to effectively shorten connecting members 53.Furthermore, the tapering of spacer 63 imparted a corresponding taper intensile member 50, but other contours (i.e., protrusions andindentations, may also be formed by modifying the surfacecharacteristics of spacer 63.

Following the use of laminating apparatus 60 to secure polymer sheets41′ and 42′ to opposite sides of tensile member 50 and impart thecontour, a bonding apparatus 70 is utilized to form peripheral bond 44between polymer sheets 41′ and 42′. Referring to FIG. 18, bondingapparatus 70 is depicted as including an upper portion 71 and a lowerportion 72 that each define a pair of ridges 73 with a general shape ofthe outline of chamber 33. Referring to FIG. 19A, the components ofchamber 33 are located between upper portion 71 and lower portion 72. Inorder to properly position the components, a shuttle frame or otherdevice may be utilized. Once positioned, portions 71 and 72 translatetoward each other and begin to close upon the components such thatridges 73 extend around tensile member 50 and compress polymer sheets41′ and 42′ together, as depicted in FIG. 19B. Heat from bondingapparatus 70 or heat applied to polymer sheets 41′ and 42′ prior tobeing located within bonding apparatus 70 may be utilized to formperipheral bond 44 when compressed by ridges 73.

When bonding is complete, bonding apparatus 70 is opened and chamber 33and excess portions of polymer sheets 41′ and 42′ are removed andpermitted to cool, as depicted in FIGS. 19C and 20. A fluid may beinjected into chamber 33. The excess portions of polymer sheets 41′ and42′ are then removed, thereby completing the manufacture of chamber 33.As an alternative, the order of inflation and removal of excess materialmay be reversed. As a final step in the process, chamber 33 may betested and then incorporated into midsole 31 of footwear 10.

Chamber 33 exhibits a tapered configuration between heel region 13 andforefoot region 11. Although tensile member 50 initially has anon-tapered configuration, the application of different degrees ofpressure and heat to areas of tensile member 50 during the laminatingprocess or other manufacturing steps may impart a taper to tensilemember 50, which imparts the taper to chamber 33 between heel region 13and forefoot region 11.

Second Manufacturing Process

Another example of a suitable manufacturing processes for chamber 33will now be discussed. With reference to FIG. 21, a thermoformingapparatus 80 that may be utilized in the manufacturing process isdepicted as including an upper mold portion 81 and a lower mold portion82. In general, the process involves utilizing thermoforming apparatus80 to (a) bond tensile member 50 to each of polymer sheets 41′ and 42′,(b) shape polymer sheets 41′ and 42′, and (c) form peripheral bond 44between the two polymer sheets 41′ and 42′. Whereas laminating apparatus60 and bonding apparatus 70 are utilized in the first manufacturingprocess described above, only thermoforming apparatus 80 is utilized inthis manufacturing process.

Initially, one or more of tensile member 50 and polymer sheets 41′ and42′ are heated to a temperature that facilitates bonding between thecomponents. Depending upon the specific materials utilized for tensilemember 50 and polymer sheets 41′ and 42′, which form barrier 40,suitable temperatures may range from 120 to 200 degrees Celsius (248 to392 degrees Fahrenheit) or more. As an example, a material havingalternating layers of thermoplastic polyurethane and ethylene-vinylalcohol copolymer may be heated to a temperature in a range of 149 to188 degrees Celsius (300 and 370 degrees Fahrenheit) to facilitatebonding. Various radiant heaters, radio frequency heaters, or otherdevices may be utilized to heat the components of chamber 33. In somemanufacturing processes, thermoforming apparatus 80 may be heated suchthat contact between thermoforming apparatus 80 and the components ofchamber 33 raises the temperature of the components to a level thatfacilitates bonding.

Following heating, the components of chamber 33 are located between moldportions 81 and 82, as depicted in FIG. 22A. In order to properlyposition the components, a shuttle frame or other device may beutilized. Once positioned, mold portions 81 and 82 translate toward eachother and begin to close upon the components such that (a) a ridge 83 ofupper mold portion 81 contacts polymer sheet 41′, (b) a ridge 84 oflower mold portion 82 contacts polymer sheet 42′, and (c) polymer sheets41′ and 42′ begin bending around tensile member 50 so as to extend intoa cavity within thermoforming apparatus 80, as depicted in FIG. 22B.Accordingly, the components are located relative to thermoformingapparatus 80 and initial shaping and positioning has occurred.

At the stage depicted in FIG. 22B, air may be partially evacuated fromthe area around polymer sheets 41′ and 42′ through various vacuum portsin mold portions 81 and 82. The purpose of evacuating the air is to drawpolymer sheets 41′ and 42′ into contact with the various contours ofthermoforming apparatus 80. This ensures that polymer sheets 41′ and 42′are properly shaped in accordance with the contours of thermoformingapparatus 80. Note that polymer sheets 41′ and 42′ may stretch in orderto extend around tensile member 50 and into thermoforming apparatus 80.In comparison with the thickness of barrier 40 in chamber 33, polymersheets 41′ and 42′ may exhibit greater thickness. This differencebetween the original thicknesses of polymer sheets 41′ and 42′ and theresulting thickness of barrier 40 may occur as a result of thestretching that occurs during this stage of the thermoforming process.

In order to provide a second means for drawing polymer sheets 41′ and42′ into contact with the various contours of thermoforming apparatus80, the area between polymer sheets 41′ and 42′ and proximal tensilemember 50 may be pressurized. During a preparatory stage of this method,an injection needle may be located between polymer sheets 41′ and 42′,and the injection needle may be located such that ridges 83 and 84envelop the injection needle when thermoforming apparatus 80 closes. Agas may then be ejected from the injection needle such that polymersheets 41′ and 42′ engage ridges 83 and 84, thereby forming an inflationconduit between polymer sheets 41′ and 42′. The gas may then passthrough the inflation conduit, thereby entering and pressurizing thearea proximal to tensile member 50. In combination with the vacuum, theinternal pressure ensures that polymer sheets 41′ and 42′ contact thevarious portions of thermoforming apparatus 80.

As thermoforming apparatus 80 closes further, ridges 83 and 84 bondpolymer sheets 41′ and 42′ together, as depicted in FIG. 22C, therebyforming peripheral bond 44. In addition, a movable insert 85 that issupported by various springs 86 may depress to place a pressure upon thecomponents, thereby bonding polymer sheets 41′ and 42′ to tensile member50. As discussed above, a supplemental layer or thermoplastic threadsmay be incorporated into tensile member 50 in order to facilitatebonding between tensile member 50 and barrier 40. The pressure exertedupon the components by insert 65 ensures that the supplemental layer orthermoplastic threads form a bond with polymer sheets 41′ and 42′.

Surfaces of upper mold portion 81 and of insert 85 are depicted ashaving a tapered configuration in each of FIGS. 22A-22C. As with spacer63 discussed above, the tapered configuration of the surfaces may impartdifferent degrees of pressure to different areas of the componentsforming chamber 33. As an alternative, the use of springs 86 withvarying degrees of compressibility may impart different degrees ofpressure to different areas of the components forming chamber 33.

As an example, tensile member 50 may initially have a thickness of 13millimeters when connecting members are in tension. In order to causebonding of between tensile member 50 and each of polymer sheets 41′ and42′, the distance between the surface of insert 85 and the opposingsurface of upper mold portion 81 may be 4.45 millimeters (i.e.,approximately 0.175 inches). In order to cause bonding and applysufficient pressure to impart the taper, the distance between thesurface of insert 85 and the opposing surface of upper mold portion 81may be 3.81 millimeters (i.e., approximately 0.150 inches_. Accordingly,a taper of 0.64 centimeters may be sufficient to impart the contouringto chamber 33. Depending upon various factors (e.g., temperature,material properties), a suitable taper may range from 0.05 millimetersto 13 millimeters.

The differences in compression due to the tapering of insert 85 or theuse of springs with varying degrees of compressibility effectivelyshorten the lengths of some of connecting member 53. More particularly,the compression (a) deforms a portion of connecting members 53 or (b)induces polymer material from polymer sheet 41′, polymer sheet 42′, orthe supplemental layers to infiltrate tensile member 50, therebyeffectively shortening the lengths of connecting members 53 in the areaswhere compression are greatest. Depending upon the degree of compressionand heat applied to the components, both deformation and infiltration ofpolymer material may cause the shortening of connecting members 53.Accordingly, differences in compression effectively impart a taperedconfiguration to tensile member 50.

When bonding is complete, thermoforming apparatus 80 is opened andchamber 33 and excess portions of polymer sheets 41′ and 42′ are removedand permitted to cool, as depicted in FIG. 23. A fluid may be injectedinto chamber 33 through the inflation conduit. In addition, a sealingprocess is utilized to seal the inflation conduit adjacent to chamber 33after pressurization. The excess portions of polymer sheets 41′ and 42′are then removed, thereby completing the manufacture of chamber 33. Asan alternative, the order of inflation and removal of excess materialmay be reversed. As a final step in the process, chamber 33 may betested and then incorporated into midsole 31 of footwear 10.

Based upon the above discussion, thermoforming apparatus 80 is utilizedto (a) impart shape to polymer sheet 41′ in order to form upper barrierportion 41 and an upper area of sidewall portion 43, (b) impart shape topolymer sheet 42′ in order to form lower barrier portion 42 and a lowerarea of sidewall barrier portion 43, and (c) form peripheral bond 44between polymer sheets 41′ and 42′. Compressive forces fromthermoforming apparatus 80 also (a) bond polymer sheets 41′ and 42′ totensile member 50 and (b) effectively shorten the lengths of some ofconnecting member 53.

Further Configurations

A suitable configuration for a fluid-filled chamber 33 that may beutilized with footwear 10 is depicted in FIGS. 3-9. A variety of otherconfigurations may also be utilized. Referring to FIG. 24A, chamber 33is depicted as having a configuration that may be utilized in heelregion 13. Whereas FIGS. 3-9 depict a configuration that extends fromheel region 13 to forefoot region 11, some configurations of chamber 33may be limited to heel region 13. Similarly, FIG. 24B depicts aconfiguration of chamber 33 that may be limited to forefoot region 11.In other configurations, chamber 33 may exhibit a lobed structure, asdepicted in FIG. 24C.

Chamber 33 is discussed above as being tapered between heel region 13and forefoot region 11. As depicted in FIGS. 7 and 8, for example, thetaper is relatively smooth such that the thickness of chamber 33continually decreases from heel region 13 to forefoot region 11. As analternative, chamber 33 may be formed to have planar areas in heelregion 13 and forefoot region 11, with a transition in midfoot region12, as depicted in FIG. 25A. In order to enhance the flexibility ofchamber 33, tensile member 50 may be formed to have relatively thinareas that form depressions in one or both of barrier portions 41 and42. For example, chamber 33 is depicted in FIG. 25B as having a pair ofdepressions in forefoot region 11 that enhance the flexibility ofchamber 33 at a location corresponding with metacarpo-phalangeal jointsof the foot. In further configurations, tensile member 50 may becompressed in a manner that provides a protrusion in midfoot region 12for supporting an arch of the foot, as depicted in FIG. 25C.

In addition to tapering, upper barrier portion 41 may be contoured toprovide support for the foot. For example, connecting members 53 may beshortened to forms a depression in heel region 13 for receiving the heelof the foot, as depicted in FIG. 26A. The depression may also be inlower barrier portion 42, as depicted in FIG. 26B. In order to formdepressions or otherwise impart curved contouring to chamber 33,laminating apparatus 60 or thermoforming apparatus 80 may be formed tohave curved surfaces. That is, in addition to being planar andnon-parallel, surfaces within laminating apparatus 60 and thermoformingapparatus 80 may be curved to impart the non-parallel aspect. In someconfigurations, chamber 33 may taper between medial side 15 and lateralside 14, as depicted in FIG. 26C. This taper may, for example, reducethe rate at which the foot pronates during running.

Peripheral bond 44 is depicted as being located between upper barrierportion 41 and lower barrier portion 42. That is, peripheral bond 44 iscentered between barrier portions 41 and 42. In other configurations,however, peripheral bond 44 may be located on the same plane as eitherof barrier portions 41 and 42. As an example, peripheral bond 44 isdepicted as being level with upper barrier portion 41 in FIG. 26D. Inthis configuration, therefore, upper polymer layer 71 is generallylimited to forming upper barrier portion 41, whereas lower polymer layer72 forms both of lower barrier portion 42 and sidewall barrier portion43. An advantage of this configuration is that visibility throughsidewall barrier portion 43 is enhanced when sidewall barrier portion 43is visible on either of sides 14 and 15 of footwear 10.

Chamber 33 is discussed above as having a configuration that is suitablefor footwear. In addition to footwear, chambers having similarconfigurations may be incorporated into other types of apparel andathletic equipment, including helmets, gloves, and protective paddingfor sports such as football and hockey. Similar chambers may also beincorporated into cushions and other compressible structures utilized inhousehold goods and industrial products. Referring to FIG. 27, a ball 90having the configuration of a soccer ball is depicted as including aplurality of pentagonal and hexagonal panels 91. Each of panels 91 havethe configuration of a fluid-filled chamber that is similar to chamber33. More particularly, and with reference to FIGS. 28 and 29, one ofpanels 91 is depicted as having a barrier 92 and a tensile member 93located within barrier 92. Each of panels 91 have curved surfaces thatcombine to form a generally spherical shape for ball 90. In forming eachof panels 91 and imparting curved contouring to panels 91, apparatusessimilar to laminating apparatus 60 or thermoforming apparatus 80 may beformed to have curved surfaces. That is, in addition to being planar andnon-parallel, surfaces within laminating apparatus 60 and thermoformingapparatus 80 may be curved to impart the curved configurations tosurfaces of panels 91.

Further Manufacturing Processes

In each of the manufacturing processes discussed above, non-parallel orotherwise contoured apparatuses are utilized to impart contour tochamber 33. More particularly, spacer 63 is secured to lower portion 62and forms a non-parallel surface with upper portion 61 in laminatingapparatus 60, and surfaces of upper mold portion 81 and of insert 85have a tapered configuration in thermoforming apparatus 80. As analternative to non-parallel or otherwise contoured apparatuses, otherfeatures may be utilized to impart contour to chamber 33.

Another configuration of thermoforming apparatus 80 is depicted in FIG.30A, wherein surfaces of upper mold portion 81 and of insert 85 have anon-tapered or substantially parallel configuration. For purposes ofreference, a first side 87 a and a second side 87 b are also identifiedin FIG. 30A. Although surfaces of thermoforming apparatus 80 arenon-tapered, contour may be imparted to chamber 33 by heating sides 87 aand 87 b to different temperatures. In general, areas of thermoformingapparatus 80 with greater temperature will induce a reduced thickness inchamber 33, and areas of thermoforming apparatus 80 with lessertemperature will induce a greater thickness in chamber 33. By heatingside 87 b to a greater temperature than side 87 a, portions of chamber33 formed in side 87 b will have lesser thickness than portions ofchamber 33 formed in side 87 a. Furthermore, by continuously varying thetemperature of thermoforming apparatus 80 between sides 87 a and 87 b,chamber 33 will be subject to a range of temperatures that may inducethe tapered configuration depicted in FIGS. 7 and 8. That is, thetemperature may continuously change along the length of thermoformingapparatus 80 in order to induce a gradual change in thickness along thelength of chamber 33.

The configuration of thermoforming apparatus 80 wherein surfaces ofupper mold portion 81 and of insert 85 have a non-tapered orsubstantially parallel configuration may also be utilized in another wayto impart taper to chamber 33. Referring to FIG. 30B, polymer sheets 41′and 42′ are depicted as having tapered configurations. Moreover,portions of polymer sheets 41′ and 42′ in side 87 a are thinner thanportions of polymer sheets 41′ and 42′ in side 87 b. As an example,polymer sheets 41′ and 42′ may taper from 1.10 millimeters (i.e.,approximately 0.045 inches) to 1.90 millimeters (i.e., approximately0.075 inches). In general, areas where polymer sheets 41′ and 42′ havegreater thickness will correspond with areas where chamber 33 exhibitslesser thickness. Accordingly, portions of chamber 33 formed in side 87a will have greater thickness than portions of chamber 33 formed in side87 b. Moreover, the continuous taper in polymer sheets 41′ and 42′ willinduce a continuous taper along the length of chamber 33, as depicted inFIGS. 7 and 8. That is, the thickness of polymer sheets 41′ and 42′ maycontinuously change in order to induce a gradual change in thicknessalong the length of chamber 33.

The invention is disclosed above and in the accompanying figures withreference to a variety of configurations. The purpose served by thedisclosure, however, is to provide an example of the various featuresand concepts related to the invention, not to limit the scope of theinvention. One skilled in the relevant art will recognize that numerousvariations and modifications may be made to the configurations describedabove without departing from the scope of the present invention, asdefined by the appended claims.

1. A method of manufacturing a fluid-filled chamber, the methodcomprising: locating a textile tensile member between two polymerelements including a first polymer sheet on a first side, a secondpolymer sheet on a second side; the textile tensile member including afirst tensile layer and a second tensile layer and a plurality ofconnecting members extending between the first tensile layer and thesecond tensile layer; applying heat at a first temperature to a firstarea of the first side of the tensile member and the polymer elements;applying heat at a second temperature to a second area of the first sideof the tensile member and the polymer elements, the first temperaturebeing greater than the second temperature to impart a non-uniformthickness to the textile tensile member; and bonding the polymerelements together around a periphery of the tensile member.
 2. Themethod recited in claim 1, including a step of continuously varying theheat between the first area and the second area.
 3. The method recitedin claim 1, further including a step of incorporating the chamber intoan article of footwear.
 4. The method recited in claim 3, furtherincluding a step of locating the first area in a forefoot region of thefootwear and locating the second area in a heel region of the footwear.5. The method recited in claim 1, wherein the step of applying heatincludes applying heat with radio frequency energy.
 6. The methodrecited in claim 1, further including compressing the tensile member andthe polymer elements; wherein the steps of applying heat at a firsttemperature, applying heat at a second temperature, and compressing thetensile member and the polymer elements are performed with a laminatingapparatus to (a) bond the polymer elements to the tensile layers, (b)decrease a length of at least a portion of the connecting members, and(c) bond the polymer elements together around the periphery of thetensile member.
 7. A method of manufacturing a fluid-filled chamber, themethod comprising: locating a textile tensile member between two polymerelements including a first polymer sheet on a first side, a secondpolymer sheet on a second side; the textile tensile member including afirst tensile layer and a second tensile layer and a plurality ofconnecting members extending between the first tensile layer and thesecond tensile layer, the first tensile layer and the second tensilelayer being substantially parallel to each other, and the connectingmembers having substantially uniform lengths; applying heat at a firsttemperature to a first area of the first side of the tensile member andthe polymer elements; applying heat at a second temperature to a secondarea of the first side of the tensile member and the polymer elements,the first temperature being greater than the second temperature todecrease a length of a first portion of the connecting members relativeto a length of a second portion of the connecting members; and bondingthe polymer elements together around a periphery of the tensile member.8. A method of manufacturing a fluid-filled chamber, the methodcomprising: locating a textile tensile member between two polymerelements including a first polymer sheet on a first side, a secondpolymer sheet on a second side; the textile tensile member including afirst tensile layer and a second tensile layer and a plurality ofconnecting members extending between the first tensile layer and thesecond tensile layer; applying heat at a first temperature to a forefootregion of the first side of the tensile member and the polymer elements;applying heat at a second temperature to a heel region of the first sideof the tensile member and the polymer elements, the first temperaturebeing greater than the second temperature to impart a non-uniformthickness to the textile tensile member; and bonding the polymerelements together around a periphery of the tensile member.
 9. Themethod recited in claim 8, including a step of continuously varying theheat between the forefoot region and the heel region.